I've bought into Captain Cooks Casino Poker for a 50% bonus of $200. It's part of the Microgaming network (which used to be Prima). The bonus cashes out at 10x raked hands per $1 (hands where you are dealt it and the rake reaches 0.25). It's a pretty decent cashout rate. I figure it will probably take around 40 table hours to complete at 1/2.
I've played a few hours already. Took a beating early, but have recovered enough to be back square with a decent chunk of the bonus completed.
The software is pretty shoddy - think Pacific. I don't think I will hang around any longer than it takes to finish the bonus. It will give me an idea if I want to chase the bonuses at 24poker (also Microgaming) for example (which cashes a bit slower, but is bigger)